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ath10k firmware sends probes on DFS channels without radar detection

Message ID 20161214195805.GA15022@w1.fi
State Not Applicable
Delegated to: Kalle Valo
Headers show

Commit Message

Jouni Malinen Dec. 14, 2016, 7:58 p.m. UTC
On Tue, Dec 06, 2016 at 06:02:52PM +0100, Jean-Pierre Tosoni wrote:
> This follows on the previous discussion
> 	"Client station sends probes on DFS channels"
> 
> Problem:
> The combination of QCA988X firmware v10.2.4.70-2 + ath10k +
> wpa_supplicant do not comply with the norm ETSI/EN 301-893
> section 4.7; because they can send probes for 600s when no
> AP is around.
> 
> Analysis:
> The problem seems to lie in the firmware, which regards the presence
> of *any* beacon as a proof that the channel is radar-clean for 600s.

I don't think this is really firmware, but cfg80211 regulatory code and
how it interacts with ath10k..

> - there is no obvious fix working in ath10k.
> - the issue does not show up with other mac80211 devices like ath9k.
> - wpa_supplicant considers this is a kernel issue [2]

There seems to be a difference between ath9k (mac80211-based Probe
Request frame sending) and ath10k (firmware) in this area for active
scanning. mac80211 uses IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR
while ath10k uses IEEE80211_CHAN_NO_IR. I'd assume this difference
results in ath10k using cfg80211 beacon hints (etc.) to update the NO_IR
flag and that might be behind the difference you see.

Could you check whether the following change gets you the behavior you
want to see here? I have not had a chance to test this yet, but based on
code review, it looks like something that brings the same behavior to
ath10k that ath9k has for this through mac80211.
diff mbox

Patch

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index aa545a1..758dbbd 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -2973,7 +2973,8 @@  static int ath10k_update_channel_list(struct ath10k *ar)
 			ch->chan_radar =
 				!!(channel->flags & IEEE80211_CHAN_RADAR);
 
-			passive = channel->flags & IEEE80211_CHAN_NO_IR;
+			passive = channel->flags & (IEEE80211_CHAN_NO_IR |
+						    IEEE80211_CHAN_RADAR);
 			ch->passive = passive;
 
 			ch->freq = channel->center_freq;